Color cinematography



pril 13 1926. 1,580,115

P. n. BREw's-rER COLOR CINEMATOGRAPHY Original Filed DSO- 28, 191 8 4Sheets-Sheet 1 lll-Llllbllllllli ll'lllllll-lllllllllllm lllmlllllllllwma-mm April 13 1926. 1,580,115 v P. D. BREwsTER COLOR CINEMATOGRAPHYoriginal Filed Dec. 28, 1918 4 sheets-sheet 2 6 s 0K2 02 0 w n v: QS/v1, m D 0 S l. m O w D D D D D D D D @D D E D D s 2 2 2 4 @D fm2, tu A@ a05 W/ m 3g 2 d 2 f m w D E E D D D D E D C 6 a ma g EM 2 Hmm o o 0% ai 19 .cm Z n n @D D D E D D D D@ D D E E D amm. ,\0\ m. 2 Mw mmmommmommmommDDEE @DED DDQ@ @DE @n.mnmnnmnmm w w i a, a, 3, D D D D n DE@ @D D D D DD .a/w w M w 1 B A April 13 1926.

P. D. BREWSTER COLOR CINEMATOGRAPHY Original Filed D 4 Sheets-Sheet 4Patented Apr. 13, 1926.

UNITED STATES 1,580,115 PATSEN orrlce.

PEBCY D. BBEWSTEB, OF EVAST ORANGE, NEW JERSEY.

COLOR CINEMATOGBAPEY.

Application led December 28, 1918, Serial No. 268,673. Renewed July 16,1925.

a full, clear, and exact description.

My present invention relates to the construction of cameras and printersfor color cinematography in which the color records are made on separatenegative films and printed on opposite sides of a double coated positiveand comprises means for securing vregistry between the images printed onthe two sides of the positive film.

My invention consists broadly in perforating the negative films whilethey are at rest in their film gates and to register the negative filmswhen printing the positive by means of these perforations, and is animprovement over myI co-pending application, Ser. No. 224,110 filedMarch 23, 1918.

I am aware that cameras for black and white have been made in which asingle lm was perforated in the camera and registry with the positivewhen printing was secured by those perforations, and that it has beensuggested in color photography to ez-:pose the separate films and toprint by contact on two sides of a double coated positive film from thetwo negative films obtained, but this process has been a failure todate, due to insuperable difficulties in registration and the object ofYUthis invention is to' provide means for securing the necessary degreeof accuracy in registration.

Registration between the images on the two sides of the positive filmshould be sufficiently accurate that when the pictures are projectedunder normal conditions, no separation, fringing or banding of thecolors about an object will be noticeable to the ordinary observer.

As the best lenses today have a .circle of confusion of about one fivehundredths of an inch and as the silver grains in the negative film willnot record any sharper image, it is apparentthat if the error inregistry between the two imagesV does not exceed that amount the pictureon the screen will be satisfactory.

My invention is illustrated in the accompanying drawings of which Fig. 1is a horizontai section through the camera; Fig. 2

is a side elevation partly in section; Fig. 3 is a plan of the lightsplitting surface of the prism; Fig. 4 -is an elevation of theperforating plate; Fig. 5 is an enlarged section through the punchplate; Fig. Gis a plan view of the punch also double size;

Figs. 7 to 10 illustrate different arrangements of the punches; Figs. 11to 16 illusa simultaneous-printer; Fig. 25 is a plan of the electriccontrolling commutator; Fig. 26 1s a diagram showing the contacts on thecommutator; Fig. 27 is' a plan of the perforations superposed forprinting; Fig. 28 is a side elevation of an optical printer.

Referring to the camera in Fig. 1, the lens 1 is'mounted on the frontboard 2, which is adapted to be moved for focusing on the base 3 betweenthe guides 4, 4 by means of rack 5 and pinion 6 (Fig. 2).

The light rays from the lens 1 enter the splitting prism 7-8 mountedbehind the lens and are divided into two color-groups. The surface 9 ofprism 7 is adapted to transmit a portion of the light rays reaching itand to reflect a portion. This surface, Fig. 3, may be partly coatedwith bands of silver and cemented to the adjoining prism 8.

The transmitted portion of the light rays pass through the red filter 10and are recorded on film 11 in the film gate while the reflected lightrays pass through the green filter 12 and are recorded on film 13, toproduce a red color-value negative image on film 11 and a correspondinggreen colorvalue image on film 13.

The films 11 and 13, as illustrated, are at right angles to each other,but they may be mounted in an relative position that is in accordancewit the angle of the light splitting prisms.

The films may be both panchromatic or one may be specially sensitizedfor light of the green color group by pinaverdol, for example and theother film sensitized for the red color group with pinacyanol. In casethe films are specially sensitized I sometimes prefer to use in front ofthe fil-m sensitized for green a yellow filter such as K 2 or K-3, whichsufficiently reduces the action on the film of the blue or violet lightrays. This type of filter is faster than the green filters and therebypermits a reduction in timev of exposure. This yellow filter is ofcourse not complementary to the red filter. The two films may bey fedthrough the exposure fields of the camera by any of the well knownintermittent feeding mec-'hanisms, such as the Lumire. or Genevamovements, the latter being illustrated. The film 11, being fed by meansof the sprocket 14, attached to the star wheel 15 and operated by thepin 'wheel 16 Von shaft'17, which also drives the film feeding mecha.-nism of film 13 through the miter gears 18 and shaft 23.

The cams 19 and 2O are mounted on the Shafts 17 and 23 respectively, andare arnanged to operate the rocker arms 21 and 22.

Film punches 24, 24 are mounted in guides 25, 25 respectively, so as toperforate the films 11- and 13 preferably inthe margin. Springs 26, 26are mounted to act between the guides and the enlarged hea-ds of thepunches 24, 24 and tend to force the heads of the punches against therocker arms and, in turn, to hold the arms against the controlling cam.

The cams are preferably so, time-d that when the film has been fed downone space Vby the sprockets, the punches vcut one or more perforationsin each film.

The film used in the camera may be without perforatio-ns and fed b-ymeans of wellknown friction feed mechanisms, but I prefer to use filmperforated with one or more perforations missing in each series of four,as shown in Fig. 11. I then prefer to arrange the punches so they willcut the master perforations 27, 27, Fig. l2, in .the space between thefeed perforations 28, 28. The

film being fed through the camera by means of sprockets on which everyfourth tooth is missing.

As shown in Fig. 12, these master perforations 27, 27 are round, butthey may be any shape desired, or made to conform to the present filmstandard as sho-wn by perforations 29, 29, Fig. 13. It is not essentialthat these perforations be equally spaced between the feed perforation28, 28 as indicated in Fig. 12.

In ease the flattened perforations are used, it is essential that theflat portions of each of the punches 24, 24 should be parallel. I

vprovide means for adjusting the punches y mounting a pin or key 30arranged to move in a slot 31, in the bushing 32 in the guide 25. Thekey is fitted without shake in the slot and the whole bushing with thepunch may be turned in relation to the guide, being secured .by thescrews 33, 33

to pa-ssbetween the die plate 34 and the guide 25, beingv held againstthe die plate.`

by means of thepressure plate 38, by the action of the springs .39, 39.v

In my invention I prefer that the punches perforate the films beforeexposure and remain in place during the exposure and are withdrawn afterthe exposure and before the films are moved, but the film may beperforated and the punches withdrawn before the exposure or the film maybe perforated during or after the exposure, without departing from myinventio- One of the punches, or sets of punches, are set arbitrarily toengage the film atv the proper point, preferably alongside of the. imageand this relation to the image is accepte as a standard and t-heposit-ion of the image on the other film in relation to its masterperforat-ions is adjusted to. conform to the relation of the first filmas a standard.

My invention provides two means by which this registrycan be secured;one by movinoone image in relation to the other and tie second, byadjusting Athe position of the punches controlling one of the. films.

The optical adjustment is secured by mounting the prisms 7-9 on theAplate 40 adapted to ti rn in the base 3 on pin 41, controlled by t ieaction offthe eapstan screw 42, between Stops 43, 43.' The clearanceholes for the screws 44, 44 in4 plate 40 are sufficiently large. topermit the necessary slight rotation of the pla-te for adjustment. Byadjusting the capstan screw the image on the film 20 is moved in azimuthin relation to the imiage on the other film. Adjustments in altitude aremade'by inserting packing or .shims under one side of the prismwl1icl1.isl1eld in place by spring clamps 45, 45. Or the plate 40 may bctapped out on either side to receive screws adaptedv .to bear againstthe prisms and tilt them in either direction desired. Any means ofadjust-ment, single or universal. maybe used for controlling theposition of the splitting prisms Vwithout departing from the spirit .ofmy invention.

In a well built camera. of this type vonlyv very small adjustments,possibly a few hundredths of an inch, are necessary to secure registryand I have found by practical experience that shims 46, 46 fittlngbetween the punch guides 25, Fig. 4, ,and the film gate provide verysatisfactory means of Securing these adjustments. My practise has beento perforate the two negative films in the camera and to register themby means of pins through the Iperforations and to measure, under amicroscope, the error in registry vertically and horizontally inthousandths of an inch and to alter the thickness of the shimscontrolling one punch guide to correct the errors thus determined.

I sometimes prefer to use shims 46, 46 between one side and top of thefilm gate and the guide and to insert the screws 47, 47

through the other side of the film gate to.

force the guide against the shims. By altering the thickness of theshims the error is quickly and accurately corrected. The screws 48, 48pass through clearance holes in the guides 25, 25 and are tapped in thefilm gate and may be loosened to permit the necessary adjustments to theguides.

The shutter 49, adapted to protect the films from the action of lightwhen the films are moving is operated by gears 50 and 51 from shaft 23.

Particularly if punches cutting the master perforations in the negativeare shaped similarly to the perforations inthe positive, I prefer tolocate the punches controlling the films exactly similarly spaced inregard to the individual images they control or the perforations aredisplaced in regard to the location of the image by the exact distancebetween one or more perforations in the positive as is illustrated bythe Figures 7 and 8. ln this case one negative would be registered onthe positive by means of its master perforation and a perforationsuitable for registry purposes in the positive, While the negative filmon the other side is registered by its master perforation and adifferent registry perforation in the positive.

if desired, the two punches Fig. 9 may he set at different levelspreferably separated by a multiple of the distance between theperforations in the positive or both punches may be set to perforate inone margin of the film as shown in Fig. 10, or a single hole may bepunched in each of the films and by means for contactingagainst thesides of the film used to secure proper registry Without departing frommy invention.

Film may be perforated in the camera, as shown in Fig. 14, withmasterperforations 52, 52 controlling the position of the images and'beforeprinting, be reperforated as in Fig. 15, using the master perforationsas a guide for the pilot pins in the reperforator and cutting registryperforations 53, 53, which preferably are located at equal distancesfrom the images, or are displaced by a distance the multiple of thedistance between perforations inthe positive, and which conform to thestandard of perforations used in the positive. I prefer that the threefilms when printing may be registered by passing properly shapedregistry pins through the registry perforations 53, 53 in the twonegative films and any registry perforations in the positive.

Fig. 16 illustrates a negative film in which the holes 52, 52 perforatedin the camera are on different levels as well as the registryperforations 53, 53 cut in the reperforator, but which conform to thestandard of perforation in the positive and can be readily registered.The camera perforations 52, 52 may be located between the images nearthe center of the film and these holes may be used to guide the pilotpins in reperforatmg.

holes 28, 28, may be used in a camera adapted to advance the film fiveperforations for every exposure. Every fifth perforation in the marginis omitted and while in the camera a single master perforation 29a Fig.18 is cut in the film, preferably near the center while at rest for eachexposure and wwhen the film is moved forward for the next exposure apin, preferably tapered is entered into the perforation to hold it inexact place before the next perforation is cut in the film. Each imageis thereby fixed in place b its relation to the perforation above andelow it. Before printing or even before development the registryperforations 30, Fig. 19, preferably shaped to conform to theperforation standard of the positive, are cut in the margin by aperforator, their location being controlled by pilot pins entering theperforations 29, 29a above and be- Film perforated, as shown in Fig. 17,with low the picture. The film may then be registered directly with thepositive by pins through its registry master perforation and a registryperforation in the positive.

By this method any change in size `of the negative, due to shrinkage indeveloping, fixing and drying the films after exposure, avoided and thenegative and positive perforation standards are exactly equal.

Negative film perforated in the camera with round holes or any specialshape, as the holes 27, 27 shown in Fig. 12, between successive groupsof feed-perforations 28, 28, Fig. 11, may be registered on positive filmperforated as shown in Fig. 20 with the specially shaped perforations28a P28, between the successive groups of standar perforations 28, 28,and after. printing (before development if desired) the positive may bereperforated with the standard perforations cutting away the originalregistry perforation 28, If desired only the holes v28?, 28EL may beperforated before or during printing and all the lstandard perforationscut in afterward. "-Ifthe negative master perforations 27, 27, and theregistry perforations 28u are larger than the standlio ardperforations28 provided in the' positive for feeding thelatter throughthe projecting machine, the positive perforations 28, .28a may be leftas they are instead of being reperforated and tlre positive film maythen be fed through the projector by the remaining perforations 28, 28.In short, it is only when the registry perforations 28a in the positivelare not large enough to receive ,the feed-claws or teeth of thefeed-mechanism of the projecting machine that the registry perforationsneed to be re-cut. n

Using the type of perforation'in which the registry master perforationin the negative conform to the positive standards of perforation it isnot neces3ary that the images` on both sides of the positive film shouldbe simultaneously printed, but the4 film may be printed in a type ofprinter illustrated diagrammatically in Fig. y22. The double'coatedpositive film 84 is fed from roll 85 in contact with the negativefilm 89 from roll 90 through the printing aper- A ture and registered bypins 93 and'printed aio 'the printer by means of the reciprocating bylight 92, the films being moved intermittently by sprocket 86 and thenegative film wound up on spool 91. The positive film 84 continuingalong in contact on the other side with the other color record nega'-tive 94, fed from roll 95 and printed by light 96 when located in theprinting aperture by pins 97, both films being fed intermittently ysprocket 87 and Wound up on spools 95 and 88 respectively.

I prefer to print the two sides of the positive simultaneously from thetwo negatives in the printer illustrated in Figs.` 23 to 26 inclusive.The negative 11, the double coated positive film 54 and the othernegative film 13 are fed or moved intermittently through feed pins 55mounted on the cross head 56,

the movements of which are controlled by the rod guides 57, 57. Thecross head'is operated by the rod 58 sliding in the oscillating guide59, which turns on shaft 6() and is drlven by the sliding connecting rod61 from the crank pin 62, mounted on disk 63 attached to driving shaft64. Solenoids A, A controlled vby the commutator 25, Fig. 19, areadapted to draw inl the iron or magnetic portion 66, 66 of the feed pins55, 55 against the action of springs 67. These feed pins tapered attheir tips, are adapted to enter the perforations of all three films andto feed or move them one ima'g space and are adjusted so as to leave theregistry perforations of the two negative films and a pair 'ofperforations in the positive films sufficiently superposed to allow theentrance of the suitably tapered registry pins l68, 68 alongside of theexposing aperture 69, open top and bottom in the printer. Suitablelights are arranged above and below the films for exposing the positivefilm, and shutter mechanisms, operating in harmony, with the filmfeeding mechanism, are provided to protect the film from the action oflight .when it is moving. The registry pins 68, 68 are operated bysolenoids C, C, controlled from the commutator 65, against the action ofthe springs 7.0, 70. The films are fed through the printer under lighttension When moving or when the registry pins are entering but, justbefore exposure, the pressure plate, adapted to fit over the films aboutthe aperture plate, and attached to covers in the solenoids D, D, isdrawn down firmly against the lower plate of the film gate and the filmsare forced firmly into contact with each other while print-ing.

If the negative films are perforated With round holes, 23, 27, Fig. 12,slnaller in size than the perforations in the positive or, in fact, ifthe negative perforations are not similar in shape to the positiveperforations, the registry pins, while locating and superposing the twonegatives have no control of the position of the images printed on thepositive film. Under these conditions each pair of images on thetvvosides of the positive will register but may not be similarly spacedin relation to the sides of the positive film or the pe forations, theresult being that the picture Willize very unsteady or weave Whenprojected on the screen. I overcome this condition in my invention byproviding pressure shoes 71, 7l to maintain 'a varying pressure on thepositive film only. These shoes are pressed against the film by means ofthe fiat spreader springs 72, 72. The core 73 in the solenoid B isforced against the spreader spring 72 constantly by fiat spring 74,which is adapted to hold the film under the desired tension when beingfed, while the solenoid B is adapted t-o grip the film and hold itfirmly after the film has been fed one image space and before theregistry pins start to enter and possibly move the positive film byfriction from the two negative films being moved'slightly in beingsuperposed by the registry pins. ,I also prefer to provide suitable sideguides in contact with the positive to prevent any side displacementsofthe positive.

-The commutator drum 65, operated in synchronism with the film feedingmechanism, is mounted in frame 75 and is adapted to hold the fourbrushes A, B, C and D against the drum. Metal segments 76, 77,

78 and 79 on the drum properly connected to an electric circuit areadapted to make contacts at the proper times with the'brushes A. B, Cand D, which are connected to the similarly lettered solenoids. Theduration of the contacts With the brushes, and consequently the actionof the solenoids is shown by the diagram in Fig. 20. The solenoids A, Aare energized while the feeding pins are moving the film, the solenoidB, B are lll) energized after the film hasstopped feeding until nearlyready for the next feeding movement; the solenoids C', C are energized ypins 84.

after the film hasrf been gripped by the solenoid B, B and 'while theexposure has been made and theIsolenoids D, D are energized after theregistering pins have entered the film perforations. Anyv suitablemechanical movements may be substituted for the solenoids illustrated,without departing from my invention.

If desired all the images can be printed on one side of the positivefilm in a single-light printer and then the positive film turned overand run through the printer again with the other negative film and theimages printcd on the other side of the fihn.

Negative film made according to my invention either with round orstandard shaped perforation may be printed in the optical printerillustrated in Fig. 28, in which one of the negative films is drawnintermittently down through the film gate 80 and the registry pin 8lused to properly locate the images in the film gate by means of amechanism similar to that described in the camera. The positive film 82is fed intermittently up through film gate 83 by suitable means, theposition of the images on the positive film being located by theregistry A suitable source of light is arranged to illuminate thenegat-ive film 11,

and a shutter arranged to protect the posi-v tive film from the actionof light when it is in motion. After the seriesof images on one side ofthe film are printed from one negative. film, the positive film isturned over and again fed through the printer with the other negativefilm; if the positive is not reversed one of the negative films must beprinted through the Celluloid. A

It is to be understood that, according to my invention, it is immaterialas to the optical system employed for exposing the negative films,whether a single or double lens system be used, whether the twonegatives are made simultaneously or consecutively and whether the twofilms run horizontally or vertically through the camera.

In place of the two separate films, an extra wide film may be used andthe negative images exposed side by side, perfo-rations being punched tocontrol the position of the images on the film. After exposure, ifdesired, these films may be vcut apart and used. as two separate filmsor the images on the double width film first on one side of the positiveand then on the other. l

For three color cinematography three separate films may be used, theposition ofthe images on the three films being controlled by suitableperforations cut in the camera and the films printed in registry bymeans 1 of these perforations, 'i

I prefer to use on all finished positive prints the generally acceptedstandard for perforating so the film may be used in any projectorwithout difficulty, but if I intend perforating the negative with holesthat are adapted to register with the positive perforations, I prefer touse in a negative special perforations of standard shape which .arelarger and spaced farther apart (across the film) than the standard sizeand separation to compensate for the shrinkage of the negative film indeveloping and drying. This shrinkage is usually considered to be aboutone per cent or slightly over, so that the negative perforations arepreferably made about one per cent larger and further separated than thepositive.

I claim- 1. In the art of color-cinematography, the improvementcomprising passing a plurality of negative films' step by step throughexposure fields, dividing the light rays from the object to bephotographed into aplurality of color-groups and projecting thecolorgroups upon said negative films to form separate series ofcolor-value negative images on the respective films, perforating thefilms, at definitely located points with respect to the images projectedthereon, while the films are at rest for exposure, to produce masterperforations, re-perforating the films with said master perforations asguides to produce registry perforations, and printing the several seriesof 'color-value negative images on opposite sides of a positive filmprovided with registry perforations conforming to the registryperforations in .the

negatives and iny printing, registering registry perforations in onefilm with registry perforations in another, whereby the images printedon one side of the positive are made to register witli'those on theother side. .i

2. In the art of color cinematography, the improvement comprisingdividing the light rays from an object to be photographed intocolor-groups and projecting the same upon separate negative films toproduce separate color-value negatives, perforating the negative filmsat definitely located points relative to the imagesY projected thereuponwhilethe films are in position for exposure to produce masterperforat-ions therein, re-perforating the negative films with the masterperforations as guides to produce registry perforations, and printingthe negative images from one of said negative films upon one side of aperforated positive film and the negative images from another of saidnegative films upon the other side, of the positive film; and inprinting, inserting pilot pins into registry perforations in thepositive and registry per-v forations in the negative to produceregistry of the images printed on the two sides of the positive.

3. In the lart of color cinematography, the improvement comprisingpassing step-bystep through'separate exposure fields negative films eachhaving along an edge a series of 4spaced groups of feed-perforations,dividing the light rays from the object to be photographed intocolor-groups and projecting the same upon the respective negative filmswhile the latter are at rest to produce thereon separate series ofnegative images, and While the films are at rest perforating the samebetween successive groups of feed perforations to produce masterpenforations at definitely located points relative to the respectiveimages projected thereon; re-perforating the negative lilms with themaster perforations as guides to produce registry perforations;providing a positive film sensitized on both sides, having in an edge aseries of spaced groups of feed-perforations and registry perforationsbetween successive groups of feed-perforations, printing the images ofone negative film upon one side of the positive and the images ofanother negative' film upon the other side of the positive, and inprinting, inserting pilot pins into the registry perforations 111 atleast two films whereby the images printed on one side of the positiveare made to reg1ster with the respective images on the other side.

In testimony whereof I afiix my signature;

PERCY D. BREwsTER.

'Certcatoffcorreetiom .y p It is .herebyl certified that in LettersPatent No. 1,586,115, granted `pril 13,1926,y

upon the application of Percy D. Brewster, of EastOrange,Newieiseyyfor'au p C lo 4Cinemato'ra, hy errors appear in the printedspecifica# Improvement m o r A D agel line 14, strike out theword..master orrection as follows: y L v alzdl flgltlllilliidperforation 7 Yread perforqtz'om; and that the said Letters Patent n.should be read-with thesecorrections therem recordof the case in thePatent Office this 11th day -of yMay,

I Signed and sealed [SEAL] Afl D.l i926, i l l J.` MOORE,

that the'samemay conform vto the:`

